Microprocessor Fundamentals - Technical MCQs

Q1:

The technique of assigning a memory address to each I/O device in the computer system is called:

A memory-mapped I/O

B ported I/O

C dedicated I/O

D wired I/O

ANS:A - memory-mapped I/O

Memory Mapped I/O:

- 16-bit device address.
- Data transfer between any general-purpose register and I/O port.
- The memory map (64K) is shared between I/O device and system memory.
- More hardware is required to decode the 16-bit address.
- The arithmetic or logic operation can be directly performed with I/O data .

Peripheral Mapped I/O:

- 8-bit device address.
- Data is transfer only between accumulator and I.O port.
- The I/O map is independent of the memory map; 256 input device and 256. the output device can be connected.
- Less hardware is required to decode the 8-bit address.
- Arithmetic or logical operation cannot be directly performed with I/O data.